/* Gamemath: a quiet reading room, not a game interface. */
:root{color-scheme:light;--paper:#f6f3ee;--white:#fffcf8;--ink:#25212a;--muted:#665e66;--plum:#533b5a;--wash:#ebe4ed;--rule:#bdb3bc;--focus:#8b315c}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font:1rem/1.65 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}
a{color:var(--plum);text-decoration-thickness:1px;text-underline-offset:.19em}
a:hover{text-decoration-thickness:2px}
a:focus-visible{outline:3px solid var(--focus);outline-offset:4px;border-radius:1px}
::selection{background:#ded0e2;color:var(--ink)}
.skip{position:absolute;left:1rem;top:-5rem;background:var(--ink);color:#fff;padding:.5rem 1rem;z-index:5}
.skip:focus{top:1rem}
.shell{max-width:1240px;margin-inline:auto;padding-inline:clamp(1.2rem,5vw,5.5rem)}
.masthead{border-bottom:1px solid var(--rule);background:var(--white)}
.masthead-inner{display:flex;justify-content:space-between;align-items:baseline;gap:1rem 3rem;padding-block:1.25rem}
.brand{font:700 1.7rem/1 Georgia,"Times New Roman",serif;letter-spacing:-.045em;text-decoration:none;color:var(--ink)}
.brand span{color:var(--plum)}
.mast-note{font-size:.69rem;letter-spacing:.15em;text-transform:uppercase;color:var(--muted);margin:0}
.nav{border-top:1px solid var(--rule)}
.nav-inner{display:flex;flex-wrap:wrap;align-items:center;gap:.15rem 1.65rem;padding-block:.5rem}
.nav a{font-size:.83rem;color:var(--ink);text-decoration:none;padding:.3rem 0;border-bottom:2px solid transparent}
.nav a:hover,.nav a[aria-current=page]{color:var(--plum);border-color:var(--plum)}
.mobile-menu{display:none}
.mobile-menu summary{cursor:pointer;font-size:.84rem;font-weight:650;letter-spacing:.03em;list-style:none;padding:.75rem 0}
.mobile-menu summary::-webkit-details-marker{display:none}
.mobile-menu summary::after{content:"+";float:right;font-size:1.15rem;line-height:1}
.mobile-menu[open] summary::after{content:"−"}
.mobile-menu summary:focus-visible{outline:3px solid var(--focus);outline-offset:3px}
.mobile-menu nav{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 1rem;padding:.35rem 0 1rem;border-top:1px solid var(--rule)}
.mobile-menu a{padding:.65rem 0;border-bottom:1px solid var(--rule);font-size:.86rem;text-decoration:none;color:var(--ink)}
.mobile-menu a[aria-current=page]{color:var(--plum);font-weight:700}
.eyebrow,.label,.source-label{font-size:.69rem;font-weight:700;line-height:1.5;letter-spacing:.14em;text-transform:uppercase;color:var(--plum)}
.page-intro{padding-block:clamp(3rem,7vw,6.5rem) 3.25rem;border-bottom:1px solid var(--ink)}
.page-intro .eyebrow{margin:0 0 1.1rem}
h1,h2,h3,p{margin-top:0}
h1,h2,.lead-figure,.big-number{font-family:Georgia,"Times New Roman",serif;font-weight:400;letter-spacing:-.035em}
h1{max-width:890px;font-size:clamp(3.15rem,7.8vw,7rem);line-height:1.02;margin-bottom:1.6rem}
.dek{font-size:clamp(1.14rem,2vw,1.48rem);line-height:1.45;max-width:690px;margin:0;color:#49404c}
.intro-bottom{display:flex;justify-content:space-between;align-items:end;gap:1rem;flex-wrap:wrap;margin-top:2.7rem;font-size:.77rem;color:var(--muted)}
.intro-bottom p{margin:0}
.reading{display:grid;grid-template-columns:minmax(145px,205px) minmax(0,710px);column-gap:clamp(2rem,7vw,7.5rem);padding-block:4rem 6rem}
.rail{font-size:.78rem;line-height:1.55;color:var(--muted)}
.rail p{margin-bottom:.85rem}
.rail .label{display:block;border-top:1px solid var(--rule);padding-top:1rem}
.prose{min-width:0}
.prose>section{padding-bottom:2.7rem;margin-bottom:2.7rem;border-bottom:1px solid var(--rule)}
.prose>section:last-child{border:0;margin:0;padding:0}
h2{font-size:clamp(2.1rem,4vw,3.35rem);line-height:1.13;margin-bottom:1.25rem}
h3{font-size:1.25rem;line-height:1.3;margin:1.8rem 0 .55rem}
p,li{max-width:68ch}
p{margin-bottom:1.1rem}
ul,ol{padding-left:1.35rem;margin:0 0 1.5rem}
li+li{margin-top:.6rem}
.note{padding:1.1rem 1.25rem;border-left:3px solid var(--plum);background:var(--wash);margin:1.7rem 0}
.note p:last-child{margin-bottom:0}
.source{font-size:.875rem;line-height:1.6;color:var(--muted);margin:1rem 0 1.6rem;max-width:70ch}
.source strong{color:var(--plum)}
.source-label{display:inline-block;letter-spacing:.08em;margin-right:.35rem}
.source .source-label{font-size:inherit}
.rule-list{list-style:none;padding:0;margin:2rem 0}
.rule-list li{display:grid;grid-template-columns:3rem minmax(0,1fr);gap:1rem;border-top:1px solid var(--rule);padding:1.25rem 0;margin:0}
.rule-list li:last-child{border-bottom:1px solid var(--rule)}
.rule-list .ordinal{font:1.3rem Georgia,serif;color:var(--plum)}
.rule-list strong{display:block;font-weight:650;margin-bottom:.3rem}
.rule-list p{margin:0}
.rule-list p.source{margin-top:.45rem}
.equation{display:flex;flex-wrap:wrap;align-items:center;gap:1rem 1.5rem;border-top:1px solid var(--ink);border-bottom:1px solid var(--ink);padding:1.5rem 0;margin:2rem 0}
.equation .big-number{font-size:clamp(2.8rem,6vw,4.75rem);line-height:1;color:var(--plum)}
.equation .explain{max-width:32ch;font-size:.9rem;line-height:1.5}
.ledger{overflow-x:auto;margin:2rem 0}
.ledger:focus-visible{outline:3px solid var(--focus);outline-offset:3px}
table{border-collapse:collapse;width:100%;min-width:450px;font-variant-numeric:tabular-nums;font-size:.92rem}
caption{text-align:left;font-size:.83rem;color:var(--muted);margin-bottom:.8rem}
th,td{padding:.8rem .6rem;border-top:1px solid var(--rule);text-align:left;vertical-align:top}
thead th{border-top:1px solid var(--ink);font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;color:var(--plum)}
tfoot th,tfoot td{border-top:1px solid var(--ink);font-weight:700}
.frequency{margin:2rem 0;padding:1.5rem 0;border-top:1px solid var(--ink);border-bottom:1px solid var(--ink)}
.frequency h3{margin:0 0 1rem}
.frequency-row{display:grid;grid-template-columns:2rem minmax(0,1fr) 3.5rem;align-items:center;gap:.7rem;margin:.8rem 0;font-variant-numeric:tabular-nums;font-size:.85rem}
.track{height:.55rem;background:#e1d9df;position:relative}
.fill{display:block;height:100%;background:var(--plum)}
.fill.nine{width:90%}.fill.one{width:10%}
.frequency figcaption{font-size:.875rem;color:var(--muted);margin-top:1rem;line-height:1.6}
.study{width:min(100%,34rem);margin:0 0 2.7rem;padding-top:1rem;border-top:1px solid var(--rule)}
.study img{display:block;width:100%;height:auto;aspect-ratio:3/2}
.study figcaption{font-size:.875rem;line-height:1.6;color:var(--muted);margin-top:.8rem;max-width:68ch}
.study-band{width:100%}
.study-band img{aspect-ratio:5/2;object-fit:cover;object-position:50% 35%}
@media(max-width:700px){.study-band img{aspect-ratio:4/3;object-fit:contain;background:var(--white)}}
.index-list{list-style:none;padding:0;margin:1.5rem 0 0;counter-reset:items}
.index-list li{border-top:1px solid var(--rule);margin:0}
.index-list li:last-child{border-bottom:1px solid var(--rule)}
.index-list a{display:grid;grid-template-columns:3.2rem minmax(0,1fr) auto;gap:1rem;align-items:baseline;padding:1.25rem 0;color:var(--ink);text-decoration:none}
.index-list a:hover .index-title{text-decoration:underline;text-decoration-color:var(--plum);text-underline-offset:.15em}
.index-number{color:var(--plum);font:1.25rem Georgia,serif}
.index-title{font:clamp(1.3rem,2.5vw,1.8rem)/1.2 Georgia,serif}
.index-arrow{color:var(--plum)}
.index-desc{display:block;font: .83rem/1.5 system-ui,sans-serif;color:var(--muted);margin-top:.35rem;letter-spacing:0}
.next{background:var(--wash);padding:2rem;margin-top:3rem}
.next p{margin:.3rem 0 0}
.footer{border-top:1px solid var(--ink);padding-block:2.3rem 4rem;font-size:.83rem;color:var(--muted)}
.footer-inner{display:flex;justify-content:space-between;gap:1rem 3rem;flex-wrap:wrap}
.footer p{margin:0}
.footer a{color:var(--ink)}
@media(max-width:700px){.masthead-inner{align-items:start;flex-wrap:wrap;gap:.5rem 1rem}.mast-note{text-align:right;max-width:22ch;letter-spacing:.09em;margin-left:auto}.nav{display:none}.mobile-menu{display:block;border-top:1px solid var(--rule)}h1,h2{overflow-wrap:anywhere}.reading{display:block;padding-block:2.5rem 4rem}.rail{display:flex;flex-wrap:wrap;gap:1rem;align-items:baseline;border-top:1px solid var(--rule);padding-top:.7rem;margin-bottom:2.5rem}.rail .label{padding:0;border:0;white-space:nowrap}.rail p{margin:0}.page-intro{padding-bottom:2.5rem}.index-list a{grid-template-columns:2rem minmax(0,1fr) 1rem;gap:.6rem}.next{padding:1.3rem}}
@media(max-width:390px){.shell{padding-inline:1.1rem}.nav-inner{gap:0 .9rem}h1{font-size:3rem}.frequency-row{grid-template-columns:1.7rem minmax(0,1fr) 2.8rem}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}